6.4.8 Working Messages

Since the Calculator is written entirely in Emacs Lisp, which is not
designed for heavy numerical work, many operations are quite slow.
The Calculator normally displays the message ‘Working...’ in the
echo area during any command that may be slow. In addition, iterative
operations such as square roots and trigonometric functions display the
intermediate result at each step. Both of these types of messages can
be disabled if you find them distracting.

Type m w (calc-working) with a numeric prefix of 0 to
disable all “working” messages. Use a numeric prefix of 1 to enable
only the plain ‘Working...’ message. Use a numeric prefix of 2 to
see intermediate results as well. With no numeric prefix this displays
the current mode.

While it may seem that the “working” messages will slow Calc down
considerably, experiments have shown that their impact is actually
quite small. But if your terminal is slow you may find that it helps
to turn the messages off.